Initial results from a longitudinal international surveillance programme for anidulafungin (2003)

Objectives: This longitudinal study evaluated the in vitro activity of anidulafungin against 880 clinical yeast isolates and 68 mould isolates from 64 medical centres in North America, Latin America and Europe. Methods: MICs of anidulafungin, amphotericin B, 5-fluorocytosine, fluconazole, itraconazole, ketoconazole and voriconazole were determined using reference method (M27-A2) guidelines. The M38-A reference method was used for the filamentous fungi, including determination of minimum effective concentrations (MECs) of anidulafungin. Results: Anidulafungin was more active when compared with fluconazole and itraconazole for Candida albicans (MIC90, 0.06 mg/L), Candida tropicalis (MIC90, 0.06 mg/L), Candida glabrata (MIC90, 0.12 mg/L), Candida krusei (MIC90, 0.06 mg/L) and Candida lusitaniae (MIC90, 1 mg/L) as well as the less-often encountered yeast species. Anidulafungin was less active against Candida parapsilosis, Candida guilliermondii and Candida famata (MIC50, 1-2 mg/L). Anidulafungin also exhibited excellent activity against all Aspergillus spp. (MEC90, less than or equal to0.03 mg/L). Anidulafungin was also evaluated comparing two end point reading criteria and two incubation intervals. Data indicate that longer incubation periods do not significantly influence overall MIC ranges. These international surveillance results for anidulafungin confirm the activity observed in studies of smaller numbers of isolates.